This small-scale case study explores the challenges and potential benefits of a wiki for students and teachers in a primary-five English-language class in Hong Kong. The study examined how the wiki's key affordances might help in scaffolding students during their collaborative writing projects. The study found that the use of a wiki in a class of primary-five students in a Chinese primary school where English is taught as a second language (L2) was perceived positively. Students enjoyed using the wiki, and the overall perception was that it helped foster teamwork and improved writing. The tracking functionality of the wiki gave in-depth information about the types of edits the students were making and helped the teacher to provide necessary support and feedback, scaffolding their editing process. Findings from this study may help illuminate how Web 2.0, specifically wikis, can help scaffold primary-school L2 writers in collaborative learning. (Contains 4 tables and 2 figures.)